Study On The Water Adsorption Of Goatskin Leather

Goatskin collagen was tanned by chrome, glutaraldehyde and chestnut extract, and the chrome-tanned sample was fatliquored by emulsified chlorinated paraffin, granulesten and sulphitated granulesten. The water adsorption behaviors of the different tanned and fatliquored goatskin collagen matrices were systematically studied. The water absorption mechanism at different temperatures was also investigated and discussed.Gravimetric analysis was used to obtain water absorption capacity of goatskin collagen. It was found that water absorption process of un-tanned goatskin collagen can be divided into three individual stages:the first stage(before 2h), water absorption capacity reaches or close to the maximum rapidly in a short time; the second stage(2-10h), water absorption capacity decreases and reaches gradually to a defined value; the third stage(after 10h), water adsorption reaches equalized-stage with a lower adsorption rate. It is more and more difficult to divide the last two stages with increasing the temperature. Particularly, the water absorption capacity of un-tanned and chestnut extract tanned samples decrease in the second stage. In all the tanned samples investigated, chestnut extract tanned sample has the largest water absorption capacity, while emulsified chlorinated paraffin fatliquored one shows the largest capacity in all the fatliquored samples. Water absorption capacity does not increase with the increase of temperature.The water absorption capacity is different at different parts of goatskin leather. The equilibrium water absorption capacity of samples at the belly section is the lowest of the leather. Temperature has a complex influence on the water absorption capacity of goatskin leather. Most samples showed the largest absorption capacity at 20℃and the smallest at 40℃, while in between at 10℃and 30℃. With increasing the temperature, the water absorption ratio raises, while the equilibrium water absorption capacity drops. Substantially, the water absorption process of leather was adjusted by three acting force, ion density, affinity with water and the crosslinking bonding of samples affect the water absorption capacity of goatskin leather. The water absorption kinetics of the chrome tanned samples was also investigated. The Lagergren first-order model and the second-order model were chose to analyze the experimental data. It was shown that the second-order model was better, in which the coefficient of determination is more than 0.9999, and the equilibrium water content of the samples deduced by the model approached to the experimental data. This indicates that chemical adsorption exists between water and collagen fibers, and the second-order model can be used to describe this kinetics process and to forecast the equilibrium water absorption capacity.